Treatment of hydrocarbon oils



Patented Aug. 7, 1934 '1 PATENT? OFFICE TREATMENT OF HYDROCARBON OILSGustav Eglofl and Jacquie C. Morrell, Chicago, 111., assignors toUniversal Oil Products Company, Chicago, 111., a corporation of DelawareNo Drawing. Application September 16, 1933,

' Serial No. 689,790 v This invention relates more particularly to therefining of relatively low boiling hydrocarbon distillates at elevatedtemperatures, especially those resulting from the conversion ofrelatively high boiling hydrocarbons at elevated temperatures andpressures.

More specifically, the-invention comprises subjecting hydrocarbon oilvapors mixed with steam to treatment with phosphoric acids in the presence of solid salts of metals such as, for example,

the salts of aluminum, zinc, tin, copper, lead, iron, mercury, cobalt,nickel, chromium, manganese, molybdenum, vanadium, tungsten, cadmium andothers, individual salts being used alone or mixed with others invarious combinations which have been found suitable for producingparticular treating effects.

The types of salts which are preferred according to the present processare those which have a definite oxidizing action upon hydrocarbon oilvapors under the preferred conditions of treatment in regard totemperature and pressure. As examples of such salts may be mentionedhypochlorites, permanganates, chromates and dichromates. 'Of the saltsmentioned as utilizable, each will exert its own particular effect uponthe reactions of treatment which is not equivalent to the other saltswhich may be used alternately, and the selection or any one foraccomplishing a particular treating efiect will be determined by mattersof expediency and trial in respect to its eiiect upon the reactions.

The acids of phosphorus which are used alternatively though withoutidentically equivalent treating action comprise those in whichphosphorus has a valence oi 5, and thus include the following acids,shown along with their formulas, melting points and other properties.

Acid Formula Properties Orthophosphoric" H:PO4(P9O5.3H:O) M. P. 38.6"0.;%

H2O 213 C. Pyrophosphoric H4PaO1(P2Os.H2O)- M. P. 61 C Metaphosphoric-HP03(P205.H10) Sublimes.

The above acids indicate from their formulas that they representdifferent degrees of hydra- (Cl. Tilt-36) ly in treating hydrocarbon oilvapors, particularly vapors arising from the cracking of heavyhydrocarbon oils such as those of approximate gasoline boiling rangecoming from fractionators of cracking plants. The treating eiiect of theacids is controlled and accentuated by the concurrent use of the variousoxidizing metal salts mentioned and also by the use of oxygen-containinggases such as' air, oxygen or ozone. The number of metal salts which maybe employed in connection with the three phosphoric acids isconsiderable and various treating effects may be obtained by usingdifierent combinations of acids and salts along with varying proportionsof steam and oxidizing gases. However, each particular combinationproduces its own treating efiect in the case of any given type of vaporsor varying types of vapors so that there is no inference that the manycombinations of treating reagents are identical in their treatingaction.

To obtain the best results with the solid metal= lic salts it is usuallypreferable to space them by supporting them on or mixing themwith-relaaction in any case will depend upon the type of I oil treatedand the conditions being employed.

The usual method of refining cracked distill ates is to subject them totreatment with sulfuric acid and alkaline solutions, including plumbitesolutions consisting of 'litharge dissolved in alkaline solutionsinvarious combinations of treatment and subsequently to subject the acidtreated product to redistillation usually in the presence of steam. Thepresent invention permits the direct treatment of the hydrocarbon vaporsfrom the cracking process, reducing the cost of reagents and eliminatingthe redistillation or rerunning operation, although it is within thescope of the invention to revaporize the product in a subsequentoperation and subject the vapors to treatment as described.

The invention is more particularly directed to the treatment of vaporsof lower boiling cracked distillates though the vapors of straight rundistillates may also be treated within the scope of the invention.

In applying the process of the invention to practice any suitableequipment may be employed vapors undergoing treatment with the acids andthe solid contact masses may be employed. The contact materials maysometimes be employed in successive strata of varying composition orsupported on superimposed trays designed to produce intimate contact.

I It has been found desirable to neutralize the vapors before or aftercondensation and .to this end the vapors may be treated with ammonia gasor pass counterflow to solutions of alkalis in auxiliary neutralizingequipment or the condensed vapors may be treated with liquid alkalissuch as solutions of caustic soda, ammonia, or the like, the traces ofreagents and reaction products remaining being washed out with waterwhen found necessary. V

The reactions involved in treatments conducted within the scope of theinvention have been observed to produce effects comparable with thoseproduced by sulfuric acid of varying strength used after the customarymethods of treatment. The amounts of phosphoric acid rebustion engines.

agent used will vary with the character of the vaporstreated from afraction of a percent to as high as 5% or higher by weight of the oilvapors treated in cases where relatively heavy treatments are desired.The amounts of oxidizing gases and steam used in conjunction with theacids of phosphorus may also be varied to produce a wide variety oftreating effects. The period during which'any particular oxidizing saltwill function either chemically or catalytically will also vary, somehaving relatively long life and being easily regenerated by simplemethods and others being effective only for short periods. In some casesby proper proportioning of the oxygen in the gas-vapor mixtureundergoing treatment, a balance maybe struck betweenthe loss of oxygenfrom the salt and its restoration by the oxygen in the mixture so thatthere is substantially no change in the composition of the solid contactmaterial.

The efiects produced upon oil vapors, particularly those produced fromthe cracking of heavy hydrocarbon oils by the use of phosphoric acids,oxidizing gases and ,solid contact substances characteristic of theinvention are in general those of polymerization or condensation 0Lrelatively highly unsaturated hydrocarbons or their derivatives,particularly their sulfur derivatives. The net result of the treatmentis thus the conversion of gum-forming and sulfur compounds into highboiling polymers or complexes 70' which are .removed by a subsequentfractionat ing step. Such groups of compounds deposit gums underordinary storage conditions or when fed to the carburetor or-manifold ofinternal com- Various temperatures of treatment may be asts employed,for example, from 250-600 FR, more or less, and the pressures may besubatmospheric, atmospheric, or superatmospheric. While the results mayvary with the conditions employed, the pressures and temperatures arechosen so that the hydrocarbons are treated substantially in the vaporphase. I

As specific examples of the operation of the invention and of theresults obtained, a California .cracked distillate of approximatelymotor fuel boiling range may be vaporized and subjected to treatmentwith aqueous orthophosphoric acid (see table) of approximatelyconcentration, the vapors being mixed with small amounts of air oroxygen and steam during their passage in a downward direction .through astationary mass of fullers earth upon which cobalt chromate has beendeposited in an amount approximately equal to one-third the weight ofthe fullers earth. The phosphoric acid may be used in an amountequivalent to approximately 5 pounds per barrel. Steam is used at therate of approximately 2 pounds per barrel. The untreated product mayshow a gum content of approximately 450 mgs.

per cc. and have a reddish-brown color, with 100 of approximately 22mgs. and a colorof 25 on the Saybolt scale. The sulfur content may befound to be as low as 0.1%.

In the case of a mixed Mid-Continent and West Texas cracked distillatetreated with approximately the same amounts of reagents, the gum contentmay be reduced from 275 mgs. to 20 and the color raised from a lightamber to approximately 25 on the Saybolt scale. The sulfur content maybe reduced from 0.45% to about 0.15%.

The process is particularly suitable to the treatment of crackeddistillates produced from California oils. In some cases the untreateddistillates may contain 500 mgs. of gum and have a dark reddish colorwhile the treated distillates color of 25 to 30 on the Saybolt scale.The sulfur content may be reduced from 0.48% to 0.12%.

The foregoing description and examples have disclosed a processapplicable to the treatment "may have a gum content of only 40 mgs. anda of hydrocarbon oil vapors which has a wide applicability and iscapable of great variations in the methods of operation and the amountsof reagents employed. Therefore, the specific cases cited are not to beconstrued in a limiting sense upon the broad scope of the invention asmany other modifications and examples can be given.

We claim as our invention: v 1. A process for refining relatively lowboiling hydrocarbon distillates, which comprises subjecting saiddistillates while in heated vaporous con- 1'35 dition to the action ofphosphoric acid in the presence of a solid salt of a metal capable ofexerting a mild oxidizing action. I

2. A process for refining relatively low boiling hydrocarbondistillates, which comprises subjecting said distillates while in heatedvaporous condition to the action of phosphoric acid in the presence ofsteam and of a solid salt of a metal capable of exerting a mildoxidizing action.

3. A process for refining relatively low boiling cracked hydrocarbondistillates, which comprises subjecting'said distillates while in heatedvaporous' condition to the action of phosphoric acid in the presence ofa solid salt of a metal capable of 15 exerting a mild oxidizing action.

presence of steam and of a permanganate of a metal.

6. A process for refining relatively low boiling hydrocarbondistillates, which comprises subjecting said distillates while in heatedvaporous condition to the action of phosphoric acid in the presence ofsteam and of a chromate of a metal.

GUSTAV EGLOFF. JACQUE C. MORRELL.

